diff --git a/bin/user/GTS.py b/bin/user/GTS.py
index 230ad99..3546f85 100644
--- a/bin/user/GTS.py
+++ b/bin/user/GTS.py
@@ -1059,7 +1059,7 @@ def get_aggregate(self, obs_type, timespan, aggregate_type, db_manager, **option
         
         # aggregation types that are defined for those values
         if aggregate_type not in ['avg','max','min','last','maxtime','mintime','lasttime']:
-            raise weewx.UnknownAggregation("%s undefinded aggregation %s" % (obs_type,aggregation_type))
+            raise weewx.UnknownAggregation("%s undefinded aggregation %s" % (obs_type,aggregate_type))
 
         if timespan is None:
             raise weewx.CannotCalculate("%s %s no timespan" % (obs_type,aggregate_type))
diff --git a/changelog b/changelog
index f791027..96a2901 100644
--- a/changelog
+++ b/changelog
@@ -61,3 +61,4 @@
 * property "length"
 0.8b1 06nov2022
 * docu
+* bug fixes